FR2644708A1 - DEVICE FOR SEPARATING TWO NON-MISCIBLE LIQUIDS AND APPLICATION THEREOF - Google Patents

Abstract

The invention relates to a device for promoting the separation and / or contact of two immiscible liquids, said device comprising at least one supply line 26 with an emulsion of the two liquids of a set of tubes, in each of which is arranged. in the direction of its length, along at least part of the latter, a bundle of fibers having a preferential wettability by one of the two liquids, said assembly being connected to a settling tank 29 in which the two liquids separate, the settling tank being equipped with discharge pipes for each of the two liquids. According to the invention, the tubes are delimited by two walls, separated by a substantially constant distance, and by a corrugated element, inserted between these walls and in contact alternately with each of them by its corrugations.

Description

Device for separating two non-liquid

  miscible and application of this device.

  The present invention relates to a device for promoting the separation and / or the contact of two liquids. It concerns more particularly the separation of the water contained in the crude oil and / or the contact of water and crude oil, therefore, the desalting of

crude oil.

  It is to this application that reference will be made in more detail below, but it is clear that the device object of the invention can be used for the separation of other pairs of immiscible liquids that the couple

water-crude oil.

  On leaving the exploitation well, the crude oil is mixed with a greater or lesser amount of water containing salts in solution (sodium chlorides, magnesium, calcium), which is the subject of a first separation. , on the very field of exploitation. The oil that reaches the refineries still contains a certain amount of salt water and, before further processing, it must be disposed of. This operation is generally carried out by injecting water into the crude and by emulsifying this mixture to form an aqueous phase dispersed in the

  hydrocarbon phase, in the form of very fine droplets.

  This aqueous phase has captured the residual salt water initially present in the crude oil. Then separating the aqueous phase from the hydrocarbon phase by breaking the formed emulsion, optionally after adding a demulsifier, in a suitable device such as an electrostatic desalter, to achieve the coalescence of the water droplets, recovering a crude oil that contains only a small fraction of the water

and salts.

  The efficiency of the desalting process depends on the quality of the "washing" of the crude oil and thus the contact surface between the water and hydrocarbon phases. This surface is all the greater as the drops of water are smaller, which nevertheless has the effect of complicating the coalescence of the drops of water necessary for the separation of the two phases, an emulsion of drops of water very fine being often stable and, therefore, difficult to break. In practice, the desalting yield Rd, by such methods, is calculated by the relation: [Salts] input - [Salts] output Rd = x 100 [Salts] entry in which [Salts] is the salt concentration of the salt. hydrocarbon, respectively upstream and downstream of the

desalting operations.

  Rd is generally in the range of 70 to 90% for a desalter operating properly. However, the presence of residual sodium chloride, magnesium and calcium chloride in the crude oil thus treated results in considerable increases in the cost of subsequent operations carried out on this crude, such as additional consumption of catalytic cracking catalyst and excessive formation. from coke to visbreaking. We know, by the French patent application filed May 7, 1986, in the name of the Applicant, and published November 13, 1987, under No. 2,598,429, a method and a device for improving the separation of water and crude oil by passing the mixture on a

  fiber bundle disposed within a tube.

  According to this patent application, it is possible to use a plurality of tubes depending on the flow rate of the

water-crude oil mixture.

  The Applicant has now established that it is possible to simply achieve this set of tubes using the technique used to achieve heat exchangers, such as those described in the French utility certificate N 2,515,328. In such exchangers, the chambers in which the fluids circulate are separated by a sandwich assembly formed of three superimposed sheets of sheet metal, namely two flat sheets between which a corrugated plate is arranged,

  the undulations extend transversely.

  The present invention therefore aims at providing a device for separating the two immiscible liquids constituting the two phases of an emulsion and, more particularly, for treating a water emulsion in crude oil, which ensure a much more thorough desalting. of this, which can reach and exceed 95% of

the initial salt content.

  The invention also aims at providing such a device of this type that can be used continuously without any significant increase in the cost of the usual processes for desalting crude oil, using simple means and

  already used in other technical fields.

  The invention therefore relates to a device for promoting the separation and / or the contact of two immiscible liquids, said device comprising at least one supply line in an emulsion of the two liquids of a set of tubes, in each of which is disposed, in the direction of its length, in at least a part thereof, a fiber bundle having a preferential wettability by one of the two liquids, said assembly being connected to a settler in which the two liquids separate , said decanter being equipped with pipes for discharging the two liquids, said device being characterized in that the tubes are delimited by two walls, separated by a substantially constant distance and by a corrugated element, inserted between these walls and in contact alternately with each of

they by its undulations.

  The invention also relates to a device for desalting a hydrocarbon feed, in particular crude oil, comprising a desalter, at least one line for the introduction into this desalter of a water emulsion and said hydrocarbon feedstock at least one pipe for discharging the separated salt water phase into said desalter and at least one pipe for removing it from the hydrocarbon phase, said device comprising, arranged on the introduction line of the emulsion of water and hydrocarbon feedstock, before the desalter, and / or on the discharge pipe of the hydrocarbon phase, before a decanter, at least one enclosure containing a set of tubes, in each of which is arranged in the direction of its length, according to at least a part thereof, a fiber bundle having a preferential wettability by water, or by the hydrocarbon feed, said device being characterized in that the tubes are delimited by two walls separated by a substantially constant distance and by a corrugated element inserted between these walls and in contact alternately with

  each of them by its undulations.

  Due to the preferential wettability of the fibers by one of the two liquids, the water or the hydrocarbon phase in the case of desalting, the drops of said liquid will tend to coalesce with each other, to sheathe the fibers and to flow out. along them, thus creating a continuous film increasing the possibility of capturing residual drops, without forming an emulsion of very fine droplets of one of the two

  liquids inside each other.

  In the case of a crude oil desalting device, the enclosure containing the tubes equipped with a bundle of fibers may be placed upstream and / or downstream of the desalter. If it is placed upstream of the desalter, a transfer of the salt in the desalting water will thus take place before the mixture reaches the desalter, and the separation therein of the salt water phase and the hydrocarbon phase phase will be facilitated by the fact that one of the liquids will flow preferentially along the fibers, generally with a speed different from that of

  the other liquid, because of their difference in viscosity.

  Under the conditions of implementation of the desalting process, and taking into account the fact that the quantity of desalting water is significantly lower than the quantity of oil, it is possible to use fibers having a

  preferential wettability by water.

  If the chamber containing the tubes equipped with a bundle of fibers is placed upstream of the desalter, the supply pipe may be fed with a mixture of water and crude oil without providing the mixing valve usually used to intimately mix the water and crude oil. Thanks to the fibers of the bundle, the contact surface between the water and the crude oil will be sufficient, without the need to use droplets of very small diameter, which will then facilitate separation.

phases.

  In the case where this enclosure is placed downstream of the desalter, the fibers will preferably have a preferential wettability by water, so that the droplets of salt water remaining in the hydrocarbon phase at the outlet of the desalter coalesce on the surface of said fibers. by forming a substantially continuous film therein. At the downstream end of the bundles of fibers, the residual aqueous phase will thus be substantially separated from the water and may be collected in a separator by decantation. Depending on the desired effects and the conditions of the treatment, it is possible to use polymer fibers, for example polyamide fibers, glass fibers, boron, carbon, stainless steel or any other fiber having good hydrophilic properties. The bundle of fibers will be fixed inside the tube that it will equip so as to occupy substantially all of its cross section. The filling rate of the tube will be chosen according to the desired effect. It may be of the order, for example, from 5 to 80% and, preferably, from 10 to 50%. Similarly, the diameter of the fibers may vary and be between 40 and 400 microns, without this area has a limiting character. The mixture of liquids circulating in the conduit may be at temperature

  ambient or at a higher temperature.

  In the desalting application, temperatures of at least about 50 C have been found to be favorable for efficient desalting. As will be seen below, the desalting efficiency using the device according to the invention may exceed 95%, and is greater than that obtained with the only desalter under the same conditions

treatment.

  In all cases, the tube or tubes equipped with a bundle of fibers will preferably be arranged vertically or obliquely, to facilitate the flow of liquids by gravity. The pressure drop between the two ends of the duct is small,

  in general less than 100 kilopascals.

  The accompanying drawings, which are not limiting in nature, illustrate various forms of implementation of the invention. In these drawings: FIG. 1 is a schematic view of a device according to the invention, with the assembly of fiber bundle tubes arranged upstream of a desalter; Figure 2 is a schematic view of a device according to the invention, with the assembly of fiber bundle tubes disposed downstream of a desalter; Figure 3 is a cross section of an enclosure containing the set of tubes, along the line III-III of Figure 4; Figure 4 is a section along the line IV-IV of Figure 3; FIG. 5 is a schematic view showing a

fiber bundle.

  In the embodiment of FIG. 1, the crude oil supply line 1 of the electrostatic desalter 2 is supplied with desalting water via line 3. Downstream from the point of connection of lines 1 and 3 is usually provided a valve mixture for intimately mixing the water and the oil in the form of very fine droplets, so as to ensure an important

  contact area between the two phases.

  In this case, this valve is removed and the line 1 is connected to the top of a vertical enclosure 4, containing a set of tubes, each tube containing

  a bundle of fibers attached to the upstream end of the tube.

  The fibers have a preferential affinity for water and the water drops wet them to form a continuous film, which flows along the associated fiber. Note the large exchange surface that exists between water and crude oil throughout the many fibers for a given amount of water, which facilitates and increases the desalting of oil. At the bottom of each tube, a partial separation of the desalting water and the crude oil has thus occurred and the mixture obtained can be evacuated by a line 7 to the base of the desalter 2, where the crude oil separation / water will be completed. The desalted crude oil phase 9 can be evacuated in the usual way to the upper part of the desalter by a line 10, while the water 11 can

  be evacuated at its base by line 12.

  In the embodiment of Figure 2, the

  desalter 20 is supplied with crude oil via line 21.

  Desalting water is introduced into the line 21 via a line 22, downstream of which is provided, in the usual way, a mixing valve 23. The salt water phase 24

  separated in the desalter is evacuated at the base of this

  ci by a line 25, while the hydrocarbon phase 19 is discharged at the top by a line 26 to a vertical enclosure 27 containing a set of tubes,

  each tube containing a bundle of fibers.

  The enclosure 27 is connected at its downstream end to a settler 29, and the bundles of fibers protrude outside the end of the tubes in a central portion of the settler, bounded by a cylindrical partition 30. The settler 29 is heated to using hot water, introduced by line 31 into a jacket 32 and evacuated

by line 33.

  The fibers of the bundles, which occupy substantially all the cross section of the tubes, are preferably wettable by water, so that the salt water droplets remaining in suspension in the separated hydrocarbon phase in the desalter are applied against these fibers coalesce and form a substantially continuous film, which flows to the clarifier 29. The water phase thus separated is discharged at the bottom of the settling tank via the line 36, while the crude oil 34

  is recovered at the top by line 37.

  Figures 3 and 4 show an enclosure containing a set of tubes, in which can be

arranged bundles of fibers.

  In this embodiment, the enclosure 50 is constituted by a cylinder 51 equipped with a cover 52 and

from a background 53.

  The cover 52 and the bottom 53 are provided with openings 54 and 55 for respectively introducing and withdrawing the

mixture of crude oil and water.

  The enclosure 50 contains a central cylindrical core 56, whose fixing means have not been represented

for the sake of simplification.

  The wall 51 of the enclosure 50 and the core 56 form a chamber 57, in which is disposed a corrugated sheet 58 which is in alternating contact by its corrugations with the wall 51 and the core 56 to form with them a plurality of tubes 59. In each tube is arranged a

  fiber bundle 60 attached to a fastening system 61.

  The fibers 62, for example polyamide, have a length of 2 meters. There may be 10.000 per beam, their diameter being 120.10-4 cm. They are set in a collar 63 equipped with a hook 64, in order to

  ability to hook the beam to the fastening system.

  Depending on the flow rate of the crude oil to be desalinated, the number of tubes will be adapted, possibly making several chambers 57 delimited by concentric walls, between which are inserted

wavy elements.

  In an embodiment that is particularly simple to manufacture, it will also be possible to use a single chamber defined by a single wall with a spiral cross-section, between the contiguous parts of which is

inserted a corrugated element.

  It has been mentioned in this description that

  separation of water and crude oil in the case of desalting it, but it is understood that can be separated, with the device according to the invention, other water-hydrocarbon couples, by dehydration in using hydrophilic fibers or by picking up hydrocarbons with oleophilic fibers. Other pairs of liquids, such as water and

edible oils.

  The following example illustrates a form of implementation

of the invention.

EXAMPLE

  This example concerns the desalting of different

crude oils.

  Tests A, B, C, D and E were carried out with a device according to the invention, such as that represented in FIG. 1, and control tests TA, TB, TC, TD and TE, with a conventional desalter such as than that shown in Figure 2, but limited to the dashed rectangle, the chamber with tubes containing fibers being removed. The dipositif according to the invention comprises twenty five tubes each provided with a bundle of 10,000 polyamide fibers of a length of 2 meters and a diameter of

  120.10-4 cm. Each tube has a fill rate of 30%.

  The results obtained are shown in the table below.

  after. The related captions appear at the end

of the Board.

  : 001: 001: 8'86: 86: 8'86: 9'66: (L) 2u'I Z:

: ....: .... TO .... TO ....-...

  : úc56: 96S6: 8 68: ZcZ6: 116: Z'ú6: (9) a2uBfssa%: omm-m: ____: -----: - -: _ (5) idd ue: S :: asnanD-s asiRd ml: ::::::: ap sainq: ioapolpq ::: O 17: 0SI: OZI: OZ>: 08: oz>: a znauae: uoTlIvl: to-- - - - - - - -: - uvzpp : :::::: :() mdd ue: oz :: :: ::: znnq ajold:: ú: 'Z: ú: ú'Z: S'Z: 6'1: np sls uae 2naueal: to - - - - - - - -: s; q of: ::: ....: (gj mdd uae:: 0: 0: O: O: 0: O: yesq year: o9d: O000: LIZ: 0558: ú069: 00úg: 0gs5: np deny a nauB,: its. & L: uy: ci: ú..ú l: 5ú1: 5: 0 + 1: 081 (ú) UoTiusaap: To .... ::. ..At.a.nap.

  : ____________________________ ------------------------- __ __:

  ::::::: (qalo:) md: ::::::: no zodde aed: (z) ae91no uB: 01: 9: 9: 9: I'S: 6 '': 6'5 neap SpTod -ua z:: .. ....: ..: ..: ..: ..:: g .e ::::::: (I) mdd ue :: ::::::: nq Oad ::: 19: ú79: 0'6Z: 56Z: 8Z: 0 Z: slips u aneauel:: I: ggI: I: gI: 0I: 0d: () d ua: To .. ... p .. am ::: ..: úZ19: úZ19: 1i79ú: 1179ú: 096Z: 096Z: nea na lnnaua :: S nm / - e. T iv :: lniq: 9: 7: 9ú9: 9: Z ::: bTmnTuIoAssIeN: eioJpd:

:, - - - - - - :: r :::::: -: -

  : 95: 9S: 9ú8: 9ú8: 6Z8: 6Z8: an; n, p aspiodu% lla:: ....: rs: rs: rs: rS: Ae: ai:

::: :: À À À:

:: y To1

'::': AT

: gi7L: 9SL8: 6'Z6: ú'56: (L) aSBq y:

: .....:.:. -.....--:

  : 6'19: The t8: The 69: 08 (9) a8Iesse6z: OZ (S) mdd ue: ::::: asnenbs asuqdl ap ::: 081: 05: 051: 0t7: seanqiooapgq ua ineuel: to ___ ....: ____: ....: .....: uolTl: ::::: (7) wdd ua iniq asoagpd: -uzpw: Sl: 91: 9 S: ú'ú: np slas ua ansue :: --------------------: sqadu: ::: :: (i) wdd ua 2naq aoaigd ::: 0079: 0000u: 006: 010úZ: np naked inauel: sassleuy:

:. ...: -..... ----. .....:

  : 9ú1: 9ú1: 6ú1: 6ú1: (ú) uOT2eusup ap eanlvapdmsa:

  : ...._: ----_.: ---_.: ----_: ------- --_ - ___--- __ ----- ___- :

  ::::: nxq seTozid ne laoddu.ied: 01: '9: 5'99: 9'9: 99 (z) apgnorva nea, p spTod ua z:

  : _........: ...: ....: --_: _- -: - -: - - _ ---- __- - _-_ __- -__ _ -

  (I) wdd ue:: Z7: Za: S91: to91: slas ua enua ::

  : ---_ --------_: ----: ------__ ----- __ ------_____ ::

  (I) udd ue:: Z9úS: Z9úS: 0061: 0061: ns ua inu: enaq:

  : _-------: -_-: --- -: -_ - _-- _- - ------___ ___ --__ ::

  :: s ::: ú / xua Dei::: 88 898: ú98: 98: enbTmnIoa ssse: alo29> d:

  : _ - _.: __ - _.: -___.: _-_-_ .: -__________________ _ ::

:::: a :::: anaBN ::

: ..: ......: ....

: & :: as: a: TS8S:

::: :::

(alTnS) nV'IqaVL He

26447G8

LEGEND OF THE TABLES:

  (1) In lines i (Figure 1) or 21 (Figure 2) (2) Through lines 3 (Figure 1) or 22 (Figure 2) (3) In desalters 2 (Figure 1) or 20 (Figure 2 ) (4) In lines 10 (Figure 1) or 26 (Figure 2) (5) In lines 12 (Figure 1) or 25 (Figure 2) (6)% Desalting = Concentration of salts in the crude at the entry Salt concentration in the crude at the outlet (7)% Washing = 100 A - B with A - C Concentration in salts in the water contained in the crude at the inlet A = Concentration in water in the crude at the inlet entry Concentration in salts in the water contained in the crude at the outlet B- Concentration in water in the crude at the outlet Concentration in salts in the water contained in the crude at the inlet C -% total water with respect to the crude Total water = water in the crude at the inlet * water added SJ Brut STATFJORD NF Brut NIGERIA FORCADOS AL Brut ARAB LIGHT ME Brut MEXICAIN These results show that with the device according to the invention, the desalting is better than with a device cl assique. In addition, the washing, which represents the tendency of the salts to pass in the water of decantation,

  is usually equivalent and often better.

Claims (4)

  1.- Device for promoting the separation and / or the contact of two immiscible liquids, said device comprising at least one supply line (1, 26) in an emulsion of the two liquids of a set of tubes, in each of which is arranged in the direction of its length, in at least a part thereof, a bundle of fibers (62) having a preferable wettability by one of the two liquids, said assembly being connected to a decanter (2, 29) in which the two liquids separate, the decanter being equipped with evacuation pipes for each of the two liquids, said device being characterized in that the tubes (59) are delimited by two walls (51, 56) separated by a distance substantially constant, and by a corrugated element (58), inserted between these walls and in contact alternately with each of them by its undulations. 2.- Device for desalting a hydrocarbon feedstock, especially crude oil, comprising a desalter, at least one conduit for the introduction into this desalter (2, 20) of a water emulsion and said hydrocarbon feedstock at least one pipe (12, 25) for discharging the separated salt water phase into said desalter and at least one pipe (10, 26) for removing it from the hydrocarbon phase, said device comprising, disposed on the introduction pipe (7) of the water emulsion and the hydrocarbon feedstock, before the desalter (2), and / or on the evacuation pipe (26) of the hydrocarbon phase, before a decanter ( 29) also equipped with water and hydrocarbon phase drainage pipes, at least one enclosure (4, 27) containing a set of tubes, in each of which is arranged, in the direction of its length, according to at least a part thereof, a bundle of fibers (62) having a preferable wettability by the water or by the hydrocarbon feedstock, said device being characterized in that the tubes (59) are delimited by two walls (51, 56), separated by a substantially constant distance, and by a corrugated element (58), inserted between these walls and in contact alternately with each of them by its undulations.   3.- Device according to one of claims 1 and 2,   characterized in that the tubes are defined by a plurality of concentric walls between which are inserted wavy elements.   4.- Device according to one of claims 1 and 2,   characterized in that the tubes are defined by a single spiral cross-section wall between adjacent portions of which a corrugated member is inserted.